An L-DOPA-like depressor action of L-threo-dihydroxyphenyl-serine in the rat caudal ventrolateral medulla
| Autor: | Masamitsu Nishihama, Fukuichiro Okumura, Nobuya Furukawa, Yoshimi Misu, Yoshio Goshima, Kiyohide Fujita, Takeaki Miyamae |
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| Rok vydání: | 1997 |
| Předmět: |
Male
Microinjections Central nervous system Glutamic Acid Blood Pressure Pharmacology General Biochemistry Genetics and Molecular Biology Serine Levodopa chemistry.chemical_compound Heart Rate medicine Animals General Pharmacology Toxicology and Pharmaceutics Rats Wistar Neurotransmitter Microinjection Medulla chemistry.chemical_classification Medulla Oblongata Dose-Response Relationship Drug General Medicine Rostral ventrolateral medulla Amino acid Rats medicine.anatomical_structure chemistry Droxidopa Competitive antagonist Organ Specificity Neuroscience |
| Zdroj: | Life sciences. 61(12) |
| ISSN: | 0024-3205 |
| Popis: | We have proposed that L-3,4-dihydroxyphenylalanine (L-DOPA) is a neurotransmitter and/or neuromodulator in the central nervous system (1). In this study, we investigated whether or not L- threo -dihydroxyphenylserine (L- threo -DOPS), a synthetic amino acid structurally related to L-DOPA, microinjected into the caudal ventrolateral medulla (CVLM) and the rostral ventrolateral medulla (RVLM) shows cardiovascular actions similar to those of L-DOPA in anesthetized rats. When L- threo -DOPS was microinjected into CVLM, it produced dose-dependent (0.01–3 ng) depressor and bradycardic responses. D- threo -DOPS (3 ng) produced no effect The responses to L- threo -DOPS (1 ng) were almost completely blocked by L-DOPA methyl ester (1 μg), a competitive antagonist for L-DOPA, supporting the existence of an L- threo -DOPS-sensitive recognition site for L-DOPA in CVLM. Microinjection of L- threo -DOPS into RVLM, however, showed no effect (0.001–100 ng), which contrasted with the cardiopressor action of L-DOPA applied in RVLM. In RVLM, there may exist an L- threo -DOPS-insensitive recognition site for L-DOPA. |
| Databáze: | OpenAIRE |
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